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Abstract

The White Hunter (WH) Local Fauna (LF) is one of the oldest assemblages from the Riversleigh World Heritage Area, belonging to Faunal Zone A and tentatively dated at approximately 24 Ma. The mammalian fauna has many plesiomorphic taxa and a wide range of body sizes are represented, although it is depauperate in medium to large arboreal mammals and over-represented by small to medium-sized macropodoids, vombatomorphians and carnivores. The non-mammalian vertebrate fauna also covers a wide body size range.

The palaeoenvironmental conditions at the time of deposition have been contentious, ranging from hypotheses of cold and dry woodland to warm, wet rainforest, and many climatic and vegetation combinations in between. The autecologies of various species provide only equivocal support for palaeoenvironmental conclusions.

Taphonomic and palaeoecologic data were tested herein to further illuminate palaeoenvironmental understanding. Mammalian post-cranial elements were examined for degree of weathering, abrasion, fragmentation, taxonomic bias and susceptibility to transport. No obvious bias against small vertebrates was observed. The fauna does not appear to represent a mixed-assemblage. Animals most likely died within close proximity to the site of deposition, although the absence of scavenger/carnivore damage militates against predation as the main source of accumulation. Trampling of elements may have been significant.

Results suggest that WH may have been a moderately large ephemeral water body, subject to periodic drying and fed by a slow-moving creek. The climate was cooler than the early Miocene, with a distinct wet and dry season. Surrounding vegetation may have been a type without modern analogue combining structural, but not floristic, equivalents of open dry forest and closed rainforest. There is no evidence for gradational wet open forest types, but this may represent a rapid move to closed forest. These results are reinforced by palaeocommunity analysis of Riversleigh LFs which unite WH LF with a suite of early Miocene Lfs as a similar palaeocommunity type, perhaps antecedent to them.

Author Comment

This is an abstract which has been accepted for the Riversleigh Symposium

Additional Information

Competing Interests

The authors declare that they have no competing interests.

Author Contributions

Troy Myers conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, wrote the paper, prepared figures and/or tables, reviewed drafts of the paper.

Data Deposition

The following information was supplied regarding data availability:

The research in this article did not generate any data or code.

Funding

This work was supported by a PANGEA Research Grant (2016 Round 2). Fossil research at Riversleigh is supported by Australian Research Council grants LP100200486, DE130100467, DP130100197 and DP170101420. Support received from P. Creaser and the CREATE Fund; the Queensland Parks and Wildlife Service; Riversleigh Society Inc.; Environment Australia; Associated Scientific Limited; Outback at Isa; and private supporters including K. & M. Pettit, E. Clark, M. Beavis, M. Dickson, S. Lavarack and the Rackham family The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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